This invention relates to a fertilizer spreader utilizing a swinging-type distributor pipe, and more particularly a distributory device thereof.
With this type spreader, a powder-like fertilizer fallen into the distributor pipe is distributed by the centrifugal force generated from the reciprocatively swinging movement of the distributor pipe. However, there is a tendency that a relatively large amount of the fertilizer is distributed at the time of turning of the distributor pipe at the critical points of the swinging motion thereof.
In order to have uniform distribution, U.S. Pat. No. 3,843,029 proposed to provide a shell-shaped spreading spout at the outlet end of a distributor pipe. With this spreading spout, however, as a fertilizer is merely guided by the upward slope formed on the bottom of the spout in forward, right and left directions, the obtained effect of uniformity is not satisfactory, and further the centrifugal force applied on the fertilizer is weakened during guidance by the slope so that the distribution range is minimized.
Another device has been disclosed in U.S. Pat. No. 3,979,072 wherein the outlet end of a distributor pipe is horizontally surrounded by a thin belt-shaped bracket for affecting the distribution pattern of materials to be spread. With this bracket, however, merely insufficient uniformity is obtained, and further the bracket may be fallen away from the body or destroyed during distribution as the distribution pipe reciprocatively swings at such high frequency as around 560 rpm and strong wind-pressure is applied thereto especially when the pipe returns.